Stereotyping has long been a concern to both social psychologists and society in general. Understanding the process of stereotyping is important because of the harmful effects that may result from applying a stereotype, especially a negative one, to an individual member of a group. In early research, stereotypes were conceptualized as sets of attributes perceived to be characteristic of a group. Further, the terms "prejudice" and "stereotyping" were used interchangeably, as it was assumed that these were parts of the same phenomenon. More recently, stereotypes have been conceptualized as including not only perceptions of the modal attributes, or central tendency of a group, but also perceptions of the variability of group members with respect to those attributes. Research also indicates that stereotypes and prejudice can exist independently of each other; that is, beliefs about the typical attributes of a group and the perceived variability of group members are not necessarily correlated with negative feelings about the group. In order to understand the stereotyping process more fully, we need to understand how our perceptions of real-world groups develop and how individuals mentally represent information about these groups. The proposed research is aimed at examining these issues. More specifically, the proposed research examines how stereotypes of in-groups and out-groups change as individuals change group membership and status within their group. The work focuses on change in perceived group variability, perceived central tendency, perceived valence, and the use of subgroups to represent variability information about social groups. Data will be gathered from college students who are joining sororities. Subjects' perceptions of their own and other sororities will be assessed four times during the initiation and membership process. The proposed research thus employs a longitudinal design to examine change in individuals' perceptions of real-world groups as they change their membership status. The outcome of this work will be a better understanding of stereotype change and, in particular, the influence of group membership on perceptions of groups. Further, this work will provide a solid foundation for a program of research aimed at examining stereotype change, using a combination of naturalistic studies and laboratory experiments.